At least now I know what happened to the Twitter "Moments" feature. First, they put it in the "Creator Studio" (along with "Analytics"), then removed it altogether on 7 December 2022.
Not all moments last. As of today we're removing the option to create Moments for most users as we focus on improving other experiences.
Don’t worry, you can still see past Moments and follow Live events on Twitter.
Most replies to the above notice seem to be complaints from those who liked to organize items for easy reference, things they were working on (particularly artists). That's understandable because the feature helped you put a bunch of tweets (and their links) under one topic heading. But there is a more critical issue. The "Moments" feature wasn't just something to promote your work; it could amplify messages throughout the Twitterverse. You can still see past Moments -- if you have the time and patience to scroll through entire timelines to find them. So those you created are not only not easy for you to see again; they are not realistically available to anyone who looks at your profile. That is another aspect of the general thrust of #NewTwitter since Elon Musk and Co. bought it.
In my case, the relevance of the issue is here.
